Filter to Include Rows
The Filter to Include Rows field is an optional parameter that enables you to filter rows in the data set. Only rows that meet the condition(s) specified are included in the analysis.
For example, to filter only chromosome 3 observations from a data set containing observations on multiple chromosomes (as indicated in a column named seqname), you could use the following simple WHERE expression:
WHERE seqname = ‘chr3’
Note: the word where has already been entered for you.
For more information about using filter fields, see The SAS WHERE Expression.